GB2150192A

GB2150192A - Mine roof support

Info

Publication number: GB2150192A
Application number: GB08330556A
Authority: GB
Inventors: David Paul Glanville
Original assignee: Dobson Park Industries Ltd
Current assignee: Joy Global Industries Ltd
Priority date: 1983-11-16
Filing date: 1983-11-16
Publication date: 1985-06-26
Also published as: GB2150192B; GB8330556D0

Abstract

A mine roof support comprises a base unit 10, a roof engaging unit 11, and at least one linkage device interconnecting the base unit and the roof engaging unit, the linkage device comprising a first link (12a, 13a Fig. 2,) interconnecting the base unit and the roof engaging unit, and a second link (12b, 13b Fig. 2) interconnecting the first link with the roof engaging unit or the base unit. The use of such a linkage device guides the roof engaging unit 11 but permits the roof engaging unit 11 to approach extremely closely to the base unit 10, so that the mine roof support can be used in mines having very thin seams. <IMAGE>

Description

SPECIFICATION Mine roof supports The invention relates to mine roof supports.

Mine roof supports are known comprising a base unit and a roof engaging unit interconnected by pivotally mounted upwardly extending hydraulic rams, and also interconnected by a linkage arranged to guide movement ofthe roof engaging unit to align the roof engaging unit with the base unit and hence maintain the relationship between the leading edge of the roof engaging unit and the mineral bearing face of the mine as the roof engaging unit moves relative to the base unit. A commonly used linkage involves two pairs of links, one pair at each side ofthe support, each link being pivotally connected at one endto the base unit and at the other end to the roof engaging unit via a single link usually in the form of a rear shield. Such a linkage is commonly known in the art as a "Lemniscate" linkage and an example is illustrated in U.K.

Patent Specification No. 21 15046 A disadvantage ofthis known linkage is that if the roof engaging unit approaches very close to the base unit, as may be necessary in a mine having a very thin seam, the links of each pairtend to "stack", i.e. the links pivot into a position in which they touch one another, preventing further pivoting. Furthermore, as the roof engaging unit is lowered, the links pivot towards the rear. Thus the upper parts of the links have a horizontal component of movement which is large compared with the vertical component of movement. Hence the linkage may be forced into the goaf face of the mine and be damaged byfalling debris.

The invention provides a mine roof support comprising a base unit, a roof engaging unit, and at least one linkage device interconnecting the base unit and the roof engaging unit, the linkage device comprising a first link interconnecting the base unit and the roof engaging unit and a second link interconnecting the first linkwith the roofengaging unit orthe base unit.

Preferablythe second link interconnects the first link with the base unit or roof engaging unit.

Preferably the second link is pivotably connected to the first link, thefirst link having a sliding connection with the base unit or roof engaging unit.

The sliding connection may comprise a sliding block to which the first link is pivotally connected, the sliding block reducing wear on the pivotal connection.

The pivotal connection ofthe second link with the base unit or the roof engaging unit is preferably on the centre line of a slot in which the sliding block is mounted.

The pivotal connection between the links may be substantially halfway along the length of the first link.

Preferably the linkage is positioned towards the rear ofthe support so that it does not obstruct the miners working area towards the front of the support.

Preferably the linkage is arranged such that it folds into the support as the roof engaging unit is lowered and does not project rearwardly into the goaf.

Preferably there is a pair of linkage devices one at each side ofthe support.

The pair of linkage devices may be interconnected formovementasa single unit.

The upper ends of the said first links may be connected to the roof engaging unit by a common connection device, for example a connection bracket to which each first link is pivotally connected.

The connection bracket may be connected to the roof engaging unit by means of a Universal joint.

The roof engaging unit may be arranged so that it may rock universally about the joint whilst maintaining its distance from the face.

Preferably the roof engaging unit and base unit are capable of being urged apart by load bearing means.

Preferably the load bearing means are hydraulic.

Preferably the mine roof support has self-advancing means, for example a hydraulic ram by means of which the mine roof support may be connected to a coal-carrying conveyor adjacent the mine face.

By way of example, a specific embodiment of the invention will now be described, with reference to the accompanying drawings, in which: Figure lisa diagrammatic side view of the rear portion of a mine roof support according to the invention; Figure 2 is a perspective view ofthe linkage devices ofthe mine roof support of Figure 1, from the rear and one side; and Figure 3 is a further perspective view of the linkage devices, but looking from the front and one side.

The mine roof support partially illustrated in Figure 1 has a base unit 10 and a roof engaging unit 11. The roof engaging unit can be raised and lowered with respectto the base unit by hydraulic rams (not shown.) The roof engaging unit 11 is guided for vertical movement with respect to the base unit 10 by linkage devices each comprising a pair of interconnected links. As best seen in Figures 2 and 3there is a first left-hand link 12a, a second left-hand link 12b, a first right-hand link 13a,and a second right-hand link 13b.

In this particular embodimentthe two first links 1 2a and 1 3a are welded together by means of a central web14.

The upper ends of the first links 1 2a and 1 3a are connected to the roof engaging unit 11 by means of a common connection bracket 15 to which the links 1 2a and 1 3a are pivotally connected by means of a pin 16.

The bracket 15 is pivotally connected to the roof engaging unit 11 by means of a pin 17 which extends longitudinally ofthe mine roofsupportso that the roof engaging unit 11 is free to rock sideways to accommodate an uneven mine roof. Thus the location afforded to the roof engaging unit 11 bythe upper ends ofthe links 1 2a and 13a is a vertical location only.

The lower ends of the links 1 2a and 13a are connected to the base unit 10 by means of a pivot pin 19 which passes through a pair of blocks 18 and a spacer 23. The blocks 18 are arranged to slide horizontally in guide slots 20 provided at each side of upright portions ofthe base unit 10.

The second link 1 2b has its lower end pivotally connected to the base unit by means of a pin 21 and its upperend pivotally connected to the mid pointofthe associated first link 12a. The second link 1 3b is similarly pivotally connected between the base unit, by means of a pin 22, and the mid point of its associated first link 13a.

The effect of the linkages shown isto permitthe bracket 15 and hence the rear end ofthe roof engaging unit 11 to move upwardly and downwardly whilst constraining the roof engaging unitto follow a vertical path. In other words the roof engaging unit cannot move rearwardly or forwardly with respect to the base unit. This in turn ensures thatthe leading edge ofthe roof engaging unit, which will be closest to the face of a mine when the device is in use, will follow a predetermined path.

Since the links of each pair 12a, 13a and 12b, 13b, are offset laterally, the links will not "stack" as the bracket 15 is lowered. The upper ends ofthe links 1 2a and 1 3a can pivot inbetween the links 12b and 13b as can clearly be seen from Figures 2 and 3. This has the effectthatthe roof engaging unit 11 can approach extremely closely to the base unit 10, so thatthe mine roof support can be used in mines having very thin seams.

Figure 1 illustrates two extreme positions ofthe roof engaging unit 11. In the upper position the connection block 18 is at the rearward end of slot 20 and the roof engaging unit is in its highest position. However as also shown in Figure 1 ,the block 18 can approach the forwardmostendoftheslot20sothatthelinks adopt an almost horizontal position and provide a lower most position forthe roof engaging unit 11.

The invention is not restricted to the details ofthe foregoing embodiment. For example instead of using the connection to the roof engaging unitwhich is shown, linkages could be connected to the roof engaging unit by means of a ball joint.

Claims

1. A mine roof support comprising a base unit, a roof engaging unit, and at least one linkage device interconnecting the base unit and the roof engaging unit, the linkage device comprising a first link interconnectingthe base unit and the roof engaging unit and a second linkinterconnectingthefirstlinkwiththe roof engaging unitorthe base unit.

2. A mine roof support as claimed in Claim 1, in which the second link is pivotally connected to the first link, the first link having a sliding connection with the base unit or roof engaging unit.

3. A mine roof support as claimed in claim 2, in which the sliding connection comprises a sliding block to which thefirst link is pivotally connected, the sliding block reducing wear on the pivotal connection.

4. A mine roof support as claimed in claim 3, in which the second link has a pivotal connection with the base unitorthe roof engaging unitwhich connection is on the axis along which the pivotal connection ofthefirst linktravels.

5. A mine roof support as claimed in any one of claims 2to 4, in which the pivotal connection between the links is substantially midway between the pivots of the first link.

6. A mine roof support as claimed in any one ofthe preceding claims, in which the second link intercon nectsthefirst link with the base unit.

7. A mine roof support as claimed in any one ofthe preceding claims, in which the linkage device is positioned towards the rear ofthe support so that it does not obstruct the minerswalkway and working area towards the front of the support.

8. A mine roof support as claimed in any one ofthe preceding claims, in which the linkage device is arranged such that it folds into the support as the roof engaging unit is lowered and does not project rearwardly into the goaf.

9. Amine roofsupportasclaimedin anyoneofthe preceding claims, in which there is a pairoflinkage devices, one at each side ofthe support.

10. A mine roof support as claimed in claim 9, in which the linkage devices are interconnected for movementasasingle unit.

11. A mine roof support as claimed in claim 10, in which the upper ends ofthe said first links are connected to the roof engaging unit by a common connection device.

12. A mine roof support as claimed in claim 11, in which the common connection device comprises a connection bracket to which each first link is pivotally connected.

13. A mine roof support as claimed in claim 12, in which the connection bracket is connected to the roof engaging unit by means of a universal joint.

14. A mine roof support as claimed in claim 13, which is capable of rocking universally aboutthe joint whilst maintaining its distance from a mineface.

15. A mine roof support as claimed in any one of the preceding claims, in which the roof engaging unit and base unit are capable of being urged apart by load bearing means.

16. A mine roofsupport as claimed in claim 15, in which the load bearing means are hydraulically operable.

17. A mine roof support as claimed in any one of the preceding claims, having self advancing means.

18. A mine roof support constructed and arranged substantially as herein described, with referenceto the accompanying drawings.

18. A mine roof support as claimed in claim 17, in which the self advancing means comprises a hydraulic ram by means of which the mine roof support may be connected to a coal-carrying conveyor adjacent to a mine face.

19. A mine roofsupportconstructed and arranged substantially as herein described, with reference to the accompanying drawings.

New claims or amendments to claims filed on 8 February, 1985.

Superseded claims 1-19.

New or amended claims 1-18.

1. A mine roof support comprising a base unit, a roof engaging unit, and at least one linkage device interconnecting the base unit and the roof engaging unit, the linkage device comprising a fixed length first link interconnecting the base unit and the roof engaging unit, the interconnection with the roof engaging unit incorporating a universal joint, and a second link interconnecting the first linkwith the roof engaging unitorthe base unit.

2. Amine roofsupportas claimed in Claim 1,in whichthe second link is pivotally connected to the first linkrthièfirst link having a sliding connection with the base u nitor roof engaging unit.

3. A mrn.e roof support as claimed in claim 2, in which the sliding connection comprises a sliding block to whichthefirstlinkis pivotally connected, the sliding block reducing wearonthe pivotal connection.

4. A mine roofsupport as claimed in claim 3, in which the second link has a pivotal connection with the base unit orthe roof engaging unit which connection is on the axis along which the pivotal connection ofthefirst linktravels.

5. A mine roof support as claimed in any one of claims 2 to 4, in which the pivotal connection between the links is substantially midway between the pivots of the first link.

6. A mine roof support as claimed in any one ofthe preceding claims, in which the second link interconnects the first link with the base unit.

7. A mine roof support as claimed in any one ofthe preceding claims, in which the linkage device is positioned towards the rear ofthe support sothat it does notobstructthe minerswalkwayand working area towards the front of the support.

9. A mine roof support as claimed in any one ofthe preceding claims, in which there is a pair of linkage devices, one at each side ofthe support.

10. A mine roof support as claimed in claim 9, in which the linkage devices are interconnected for movement as a single unit.

11. A mine roof support as claimed in claim 10, in which the upper ends of the said first links are connected to the roof engaging unit by a common connection device which incorporates the universal joint.

12. A mine roof support as claimed in claim 11, in which the common connection device comprises a connection bracket connected to the roof engaging unit by means of the universal joint, each first link being pivotally connected to the connection bracket.

13. A mine roof support as claimed in any one of the preceding claims, in which the roof engaging unit is capable of rocking universally about the joint whilst maintaining its distance from a mine face.

14. A mine roofsupportas claimed in anyone of the preceding claims, in which the roof engaging unit and base unit are capable of being urged apart by load bearing means.

15. A mine roof support as claimed in claim 14, in whichtheIoad bearing means are hydraulically operable.

16 A minewofsupport as claimed in any one of the preceding claims, having self advancing means.

17. A mine roof support as claimed in claim 16, in which the self advancing means comprises a hydraulic ram by means of which the mine roofsupport may be connected to a coal-carrying conveyor adja centtoa mine face.